REM sleep critical for young brain development; medication interferes

Rapid eye movement or REM sleep actively converts waking experiences into lasting memories and abilities in young brains reports a new study. The finding broadens the understanding of children’s sleep needs and calls into question the increasing use of REM-disrupting medications such as stimulants and antidepressants.

Professor of medical sciences Marcos Frank said scientists have known that infant animals spend much of their early life in REM sleep, but little was understood about the actual nuts and bolts of REM’s ability to change or recombine memories.

Providing new insights, Frank and his colleagues documented the effects of sleep on vision development in young animals. The researchers found that brain circuits change in the visual cortex as animals explore the world around them, but that REM sleep is required to make those changes “stick.”

The scientists showed that the changes are locked in by ERK, an enzyme that is activated only during REM sleep.

“REM sleep acts like the chemical developer in old-fashioned photography to make traces of experience more permanent and focused in the brain,” said Frank.

“Experience is fragile,” he said. “These traces tend to vanish without REM sleep and the brain basically forgets what it saw.”

Frank said young brains, including those of human children, go through critical periods of plasticity – or remodeling – when vision, speech, language, motor skills, social skills and other higher cognitive functions are developed.

The study suggests that during these periods, REM sleep helps growing brains adjust the strength or number of their neuronal connections to match the input they receive from their environment, he said.

In the 1960s, Frank said surgeons noticed that delayed removal of congenital cataracts in children resulted in severe problems such as double vision and the inability to align the eyes.

“The visual cortex is very sensitive to information it is receiving and there are critical periods for its development,” he said. “If vision is blocked at these stages, then problems result.”

The study used a model based on that finding to determine the specific effects of REM sleep on vision development. Animals had a patch placed over one eye and their brain activity was monitored both while awake and during sleep.

While in REM sleep, the animals were awakened intermittently by gentle tapping on their enclosures. Controls were awakened during non-REM sleep.

Analyses showed that normal vision did not develop in animals experiencing a REM sleep deficit.

“Without REM sleep, permanent plastic changes to the visual cortex did not occur and the ERK enzyme did not activate,” said Frank.

Previously, the researchers had determined that ERK works by turning neuronal genes into proteins, which solidify the brain changes.

Frank was surprised to also discover brain activity patterns occurring in REM sleep that were similar to those seen when the animals were awake.

“It’s as if the neurons were dreaming of their waking experience,” he said.

“This is the first time these similar events have been reported to occur in the developing brain during REM sleep,” said Frank. “Up till now, there has not been strong evidence to show that waking experience reappears during REM sleep.”

He said REM sleep may be important for the development of other parts of the brain beyond the visual cortex and its effects may continue throughout a lifetime.

The study “has big implications for our understanding of sleep in children,” said Frank.

“There is a lot of data accumulating that says the amount of sleep a child gets impacts his/her ability to do well in school,” he said. “This study helps explain why this might be – and why we should be cautious about restricting sleep in our children.

“We know there are different times in a child’s development when sleep needs increase – they are very high in babies but also in adolescents when their brains are changing rapidly,” he said.

“Also, it is becoming more common for pediatricians to give compounds that affect brain activity earlier in life – not just Ritalin for attention deficit disorder, but also antidepressants and other drugs,” said Frank.

“The fact is, we have very little pre-clinical research data to tell us what these drugs are doing to developing brains in both the short and long term,” he said.

“Almost all of these compounds can potentially suppress sleep and REM sleep in particular. REM sleep is very fragile – it can be inhibited by drugs very easily,” he said.

10 responses

Emilie

I agree that REM sleep is very important in brain growth and development and with that being said i think that it is especially important in young children. REM sleep allows the body to fully relax and recharge. It is also giving your mind and body a break which is useful for young children and adults seeing as they are so busy and are often cramming things into their brain. I agree with this article and think that rem sleep is very important in growth and development and that it can help with their brain development for the future.

I just wanted to add that REM-sleep is not a “restful” period of sleep…it is more calorie-consuming than many waking activities and it corresponds to higher amygdala-activation than at any other time of day or night, and is thus associated to high-valence (emotional) processing, fear-processing in particular (dreaming). Of course, REM-sleep may have multiple functions and these may change as we develop throughout life, but as a dream-researcher I want to help people understand what the various sleep stages (and especially REM-sleep) are really all about. REM-sleep is most usually the opposite of relaxation.

Jon, thank you again for your wonderful insights. Since I didn’t include any fun brain anatomy links for anyone else reading who is interested, you can read about the functions of the amygdala (or at least what we know it does) here.

I think it’s very interesting to study how our brains handle REM sleep and the effects drugs can have on our sleep. There’s so many different medications that could effect sleep patterns. It is interesting that REM sleep helps us remember things. And if medications are effecting our REM that can be a problem, especially in children. Our brains wouldn’t get the necessary time they need to go through each sleep cycle.

I’m curious what the longer term ramifications of medicating children will be. Keep in mind most medications are never actually tested on children before they hit the market, so the effects, especially to the developing brain, could be very unintended and possibly unwanted.

REM sleep is obviously an established part of the sleeping process which has been studied heavily. Much information on this topic has been established. We know that it is an important part of the sleep cycle, which disturbing or never occurring, can result in a major influence of a person’s entire life. It has been shown that REM sleep does play a role in various things such as recalling dreams. It is also known that inducing sleep with alcohol can prohibit important parts of the sleep cycle causing sleepers a new and most likely worse problem than difficulty falling asleep. If we know these facts are true then I believe this topic is undoubtedly in need of research. The fact that differences were caused in animal testing just proves this to be all the more true. Do we really know if we are helping or hurting our children by prescribing them medicine we may not truly know the effects of? Drugs will alter children in different ways than adults, so it seems they could alter the way children learn and remember. If we are disabling certain methods of growth from stimulation and new experiences, we are hindering the capabilities of our children’s development. There should be few circumstances in which prescription drugs actually hinder a child’s development while correcting another problem. Research on how REM sleep is sensitive to the storing and remembering of new data must be completed so further studies of how outside factors can manipulate this process. I am interested to follow up on this topic and learn more about what changes the processes that happen during REM sleep.

I totally agree, especially with the medicating children part. It seems like every kid has ADD now, but I would think that in a good portion of those children are just really active and developing kids. But these days in a lot of cases we want to impose adult behaviors on children.

It’s interesting to think that you need REM sleep to remember things. We always hear that our bodies need sleep to function properly, but we never hear about how it affects our memories. this post points out that without REM sleep, we could basically completely forget what we had seen or learned that previous day. As a college student, it is not uncommon for me to only get a few hours of sleep or less a night. This gives me a different perspective on how much sleep I actually need to get. If I am getting very little REM sleep, then I will not be able to remember as much of what I learned in my classes that day which would make it harder when test time comes around.

This is true, which is probably why students get told all the time that late night cramming sessions are counterproductive hinthint Personally I recommend taking the day before the exam off from studying and just get a good nights rest, but that is just me.